1. Field of the Invention
The present invention relates to an endoscope and particularly concerns a frame member in an at-hand operating part, an insertion part, or a light guide connector of an endoscope.
2. Description of the Related Art
Conventionally, in endoscopes, an operating part to operate the endoscope is connected to the base of an insertion part, which is inserted into a subject. The operating part includes a curving operation mechanism, a suction valve, and an air/water supply valve and so on. Various tubes, an angle operating wire, codes, a light guide, and so on, which attach and support the above members and are provided through the insertion part, are connected to or inserted into the operating part. Further, a light guide soft part with flexibility is connected thereto, in which a light guide for introducing light from a light source disposed outside, a video signal code connected to a display and so on, and tubes for supplying and discharging air and water are inserted.
The operating part needs to support the curving operation mechanism and the like so as to positively operate them, and needs to have strength for connecting the insertion part. For example, as shown in FIGS. 8 to 10, an at-hand operating part disclosed in Japanese Patent Publication No. 2-43484 has an external component that is composed of a plastic case 1 and a rubber cover 2 and is electrically insulated. In the external component, a base plate 3 and a guide tube 4 are provided as frame members. A pulley having an angle operating wire wounded (not shown) is rotatably disposed on the base plate 3, and the angle operating wire and the contents of an endoscope are inserted into the guide tube 4 and are protected.
The base plate 3 and the guide tube 4 are connected to each other via connecting members 5 and are fixed by screws 6. The base plate 3 and the guide tube 4 allow the at-hand operating part to obtain mechanical strength.
Endoscopes need to be dipped into a chemical solution and/or to be subjected to gas sterilization after use for disinfection and sterilization. Gas sterilization is performed in an atmosphere of EOG (ethylene oxide gas) or hydrogen peroxide plasma gas. This sterilization is carried out by filling gas after reducing a pressure in a sterilizer. In general, since the endoscope entirely have an air-tight structure, in order to have equal pressures inside and outside the endoscope so as to prevent the endoscope from being damaged by a pressure difference between the inside and outside of the endoscope when a pressure is reduced, a vent is provided for connecting the inside and outside of the endoscope upon sterilization. Hence, when gas is filled, the gas enters the inside of the endoscope, and corrosion may occur if frame members made of aluminum are used.
Therefore, instead of aluminum prone to corrosion, corrosion-resistance stainless steel and titanium have been currently proposed as a frame member.
However, when stainless steel is adopted as a frame member, an at-hand operating part may be heavier and lower in operatability because stainless steel is large in specific gravity.
Meanwhile, when titanium is adopted as a frame member, in the case of a frame member having a complicated shape, working and assembling are necessary for each component having a simple shape because titanium is poor in workability and a worked shape is limited.
Against the above backdrop, a frame member with satisfactory mechanical strength, chemical resistance, size reduction, weight reduction, and workability has been desired.
The present invention has been developed in view of the above-mentioned circumstances and has its object to provide an endoscope which has a frame member being satisfactory in all of mechanical strength, chemical resistance, size reduction, weight reduction, and workability.
In order to attain the above object, the present invention is directed to an endoscope, comprising a frame member formed by using carbon fiber reinforced thermoplastic resin.
According to the present invention, since carbon fiber reinforced thermoplastic resin is used as a material of the frame member, it is possible to obtain sufficient mechanical strength and reduced weight as compared with metal. Further, carbon fiber reinforced thermoplastic resin has sufficient chemical resistance and can prevent corrosion of the frame member during disinfection and sterilization. Moreover, carbon fiber reinforced thermoplastic resin can be molded like other resins. Thus, even a complicated shape can be integrally formed.
Preferably, the frame member is a plate member provided in an endoscope at-hand operating part. Hence, the at-hand operating part can be lighter in weight.
Preferably, a tube member is connected to the plate member, and the tube member and the plate member are integrally formed. Hence, screws and the like are not necessary for connecting the tube member and the plate member. Therefore, by effectively using a space where screws and the like used to exist, the at-hand operating part can be smaller in size.
Preferably, the carbon fiber reinforced thermoplastic resin is prepared by mixing carbon fiber into a material selected from a group consisting of nylon-66, ABS, PC, PBT, denatured PPE, PPS, PET, and POM. Selection can be optionally made according to the shape and use.
Preferably, the carbon fiber reinforced thermoplastic resin contains substantially 20% to substantially 30% of carbon fiber. Hence, it is possible to achieve mechanical strength substantially equal to that of aluminum.
Preferably, the carbon fiber reinforced thermoplastic resin is a mixed material prepared by mixing crystalline material and amorphous resin; and the mixed material contains substantially 70% to substantially 80% of the crystalline resin. Hence, it is possible to improve workability such as size stability while maintaining excellent chemical resistance and mechanical strength that are advantages of crystalline resin.